it was one of several attacks nationwide, with memories of the newtown school massacre still fresh. and in bethlehem, the church of the nativity marked the arrival of christmas day with midnight mass. and the pope presided over late night services for hundreds of the faithful, in st. peter's basilica at the vatican. actor jack klugman was died in california. online, we ask "what did the world look like in 2012?" kwame holman is here to tell us. >> holman: rewind the year in photos and revisit some of the most memorable and tumultuous moments around the globe. find that slideshow on our world page. plus larry kotlikoff continues to answer questions about social security, including what happens to the benefits of those who die without a survivor. find "ask larry" on the business desk. all that and more is on our web site, newshour.pbs.org. >> brown: and that's the newshour for tonight. on tuesday, christmas day, we'll look ahead to 2013, a pivotal year for implementing the new health care reform law. i'm jeffrey brown. >> ifill: and i'm gwen ifill. we'll see you online and again here